A comprehensive set of simulations studying the influence of gas expulsion on star cluster evolution

Baumgardt, H. and Kroupa, P. (2007) A comprehensive set of simulations studying the influence of gas expulsion on star cluster evolution. Monthly Notices of the Royal Astronomical Society, 380 4: 1589-1598. doi:10.1111/j.1365-2966.2007.12209.x

Author Baumgardt, H.
Kroupa, P.
Title A comprehensive set of simulations studying the influence of gas expulsion on star cluster evolution
Journal name Monthly Notices of the Royal Astronomical Society   Check publisher's open access policy
ISSN 0035-8711
Publication date 2007-10
Sub-type Article (original research)
DOI 10.1111/j.1365-2966.2007.12209.x
Open Access Status DOI
Volume 380
Issue 4
Start page 1589
End page 1598
Total pages 10
Place of publication Oxford, United Kingdom
Publisher Oxford University Press
Language eng
Formatted abstract
We have carried out a large set of N-body simulations studying the effect of residual-gas expulsion on the survival rate, and final properties of star clusters. We have varied the star formation efficiency (SFE), gas expulsion time-scale and strength of the external tidal field, obtaining a three-dimensional grid of models which can be used to predict the evolution of individual star clusters or whole star cluster systems by interpolating between our runs. The complete data of these simulations are made available on the internet. Our simulations show that cluster sizes, bound mass fraction and velocity profile are strongly influenced by the details of the gas expulsion. Although star clusters can survive SFEs as low as 10 per cent if the tidal field is weak and the gas is removed only slowly, our simulations indicate that most star clusters are destroyed or suffer dramatic loss of stars during the gas removal phase. Surviving clusters have typically expanded by a factor of 3 or 4 due to gas removal, implying that star clusters formed more concentrated than as we see them today. Maximum expansion factors seen in our runs are around 10. If gas is removed on time-scales smaller than the initial crossing time, star clusters acquire strongly radially anisotropic velocity dispersions outside their half-mass radii. Observed velocity profiles of star clusters can therefore be used as a constraint on the physics of cluster formation.
Keyword Stellar dynamics
Methods : N-body simulations
Stars : formation
Open clusters and associations : general
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Mathematics and Physics
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